Diagnosis of latent tuberculosis infection is associated with reduced HIV viral load and lower risk for opportunistic infections in people living with HIV

Approximately 28% of the human population have been exposed to Mycobacterium tuberculosis (MTB), with the overwhelming majority of infected individuals not developing disease (latent TB infection (LTBI)). While it is known that uncontrolled HIV infection is a major risk factor for the development of TB, the effect of underlying LTBI on HIV disease progression is less well characterized, in part because longitudinal data are lacking. We sorted all participants of the Swiss HIV Cohort Study (SHCS) with at least 1 documented MTB test into one of the 3 groups: MTB uninfected, LTBI, or active TB. To detect differences in the HIV set point viral load (SPVL), linear regression was used; the frequency of the most common opportunistic infections (OIs) in the SHCS between MTB uninfected patients, patients with LTBI, and patients with active TB were compared using logistic regression and time-to-event analyses. In adjusted models, we corrected for baseline demographic characteristics, i.e., HIV transmission risk group and gender, geographic region, year of HIV diagnosis, and CD4 nadir. A total of 13,943 SHCS patients had at least 1 MTB test documented, of whom 840 (6.0%) had LTBI and 770 (5.5%) developed active TB. Compared to MTB uninfected patients, LTBI was associated with a 0.24 decreased log HIV SPVL in the adjusted model (p < 0.0001). Patients with LTBI had lower odds of having candida stomatitis (adjusted odds ratio (OR) = 0.68, p = 0.0035) and oral hairy leukoplakia (adjusted OR = 0.67, p = 0.033) when compared to MTB uninfected patients. The association of LTBI with a reduced HIV set point virus load and fewer unrelated infections in HIV/TB coinfected patients suggests a more complex interaction between LTBI and HIV than previously assumed.

Surprisingly little is known about how latent tuberculosis infection alters human physiology and immune function. Extensive statistical analyses of the large Swiss HIV Cohort Study suggests that latent tuberculosis infection can be protective in individuals with HIV.     

Individuelles Erkennen des Gesangs durch die Weibchen und Gesangsaktivit?t der M?nnchen bei der Rohrammer (Emberiza schoeniclus)

Zusammenfassung Die vorliegende Untersuchung ist der zweite experimenelle Nachweis, daß Singvogelweibchen im Freiland die Gesänge der eigenen Männchen erkennen können. Es ist zu erwarten, daß es sich um ein bei vielen Vogelarten verbreitetes Phänomen handelt. Wie gezeigt werden konnte, ergeben sich daraus weitreichende Folgen für Erklärungen zur Funktion des Gesangs und des Paarungsverhaltens.

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Individual recognition of song by the female and song activity of the male in the Reed Bunting (Emberiza schoeniclus)

Playback of tape recorded songs in the field showed that females of the Reed Bunting approached only songs of their mates. This is the second experimental evidence for songbirds that females are able to recognize the songs of individual males. This ability of the females is seen as a possible cause for increase of song activity after the start of breeding. Females should choose the male next to their nest to get his help for rearing their young. Therefore, the males should stay near the nests and sing to ensure that they are recognized and chosen during the next fertile period. Alternative hypotheses are discussed.

     

Effects of three Caribbean cleaner shrimps on ectoparasitic monogeneans in a semi-natural environment

Most research on cleaning symbioses on coral reefs has focused on fish clients being cleaned by smaller fishes. While many shrimps and other crustaceans are reported as cleaners, whether they remove parasites from fish hosts and can effectively regulate populations of ectoparasites is unclear. The effects of Pederson shrimp (Periclimenes pedersoni), spotted shrimp (P. yucatanicus), and banded coral shrimp (Stenopus hispidus), on the parasitic monogenean Neobenedenia melleni on a host reef fish, blue tang (Acanthurus coeruleus), were investigated. The abundance and size of N. melleni from fish with and without access to shrimps in a semi-natural macrocosm was quantified. P. pedersoni had a strong effect on both the abundance and size of parasites. In contrast, P. yucatanicus and S. hispidus had no effect on the abundance of parasites but had a small yet statistically significant effect on average size. These data suggest that P. pedersoni can play a significant role in the biological regulation of at least some ectoparasites on Caribbean reef fishes, but further suggest that some other shrimps regarded as “cleaners” may have little or no effectiveness at removing parasites and underscore the need for further verification before this term is applied.     

Metabolic heterogeneity of muscle fibers classified by myosin ATPase

Summary Muscle fibers re commonly classified histochemically into three types by the staining intensity for myosin ATPase combined with those for metabolic enzymes. Preincubation at pH 4.6 gives rise to three staining intensities of myosin ATPase which are also used for fiber typing. The two classification systems were compared by computer analysis of the individual staining profiles of over 2,500 fibers, and found not to be equivalent. The analysis showed metabolic heterogeneity among the fiber groups distinguished according to their differences in myosin ATPase.     

Metabolic transitions in rat jaw muscles during postnatal development.

The program of acquisition of adult metabolic phenotypes was studied in three jaw muscles in order to determine the link between muscle metabolism and functional development. During early postnatal stages, there were similar transitions in the masseter, anterior digastric, and internal pterygoid muscles with respect to fiber growth, fiber type composition, and whole muscle energy metabolism. Oxidative capacity, as judged by the activities of the enzymes succinate dehydrogenase (SDH), malate dehydrogenase (MDH), and beta-hydroxyacyl CoA dehydrogenase (beta OAC), rose sharply after birth to reach near maximal levels by 3 weeks. The capacities for glycolytic metabolism represented by lactate dehydrogenase (LDH), and for high-energy phosphate metabolism represented by adenylokinase (AK) and creatine kinase (CK) activities, rose gradually, not reaching peak values until 6 weeks or later. Thus, the maturation of oxidative metabolism preceded that of glycolytic metabolism in the developing jaw muscles. This was documented for individual fibers in the masseter muscle. Differential metabolic maturation among the jaw muscles was evident beyond 3 weeks. All three jaw muscles attained their specific adult fiber-type profile by about 6 weeks. This maturation program differed from that of hindlimb muscles [Nemeth et al., J Neurosci 9:2336-2343, 1989] and diaphragm muscle [Kelly et al., J Neurosci 11:1231-1242, 1991], reflecting their differential energy demands for contractile performance.